Colin Alley loves to run, and for awhile on Monday, the San Francisco resident had a really good time in Boston: Finishing the Boston Marathon in about three hours, heading away from the finish line and basking in a job well done.

Then came the two explosions, about two hours after the winners crossed the line, and his cell phone buzzed like crazy. As of Monday afternoon, two were killed and dozens were injured.

Raw Video: Watch Boston Marathon Blasts

Watch video of the explosions near the Boston Marathon finish line. (Published Monday, April 15, 2013)

Alley spoke by phone to NBC Bay Area, as he was standing in the lobby of a Boston office building, talking quickly, both because of the craziness surrounding him, and because his cell phone battery was running out.

Photos: Boston Marathon Blasts

He recalled the smoke and activity after the explosions, and then he remembered posting to Facebook that he was OK.

But the 43-year old runner, after a pause, admitted that this day shook him.

RAW VIDEO: Chopper Over Boston Marathon Explosion Aftermath

Watch raw chopper video of the activity immediately following explosions near the finish line of the Boston Marathon. (Published Monday, April 15, 2013)

"You know, this was one of those days where I actually ran a personal record, and was very excited about that," he said. "Then this happened, and it put a pall over all that."

Alley added that he now feels odd about the whole thing, worried about other runners, and "it definitely feels like the mood changed. I'm happy that I'm OK, but this is disheartening about our society."

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The following story is from Bay City News:

A Monterey County man who was one of the top finishers in the Boston Marathon today was on lockdown at a Boston hotel this afternoon after two explosions occurred near the race's finish line.

Daniel Tapia, 26, of Castroville, said he had finished running the 26.2-mile course around noon Boston time and had gone into the Fairmont Copley Plaza hotel near the finish line to grab a snack and recover.

He said he was inside the hotel when he heard what sounded like a loud pop.

Tapia said his family is with him and that he was hoping to go out to dinner tonight in Boston, but as of this afternoon that didn't seem likely.

He said a medical tent had been set up in front of the hotel, and that he has heard about severe injuries.

Initial news reports after the blast indicated that at least two people were killed and nearly two-dozen injured.

Tapia said he knows dozens of runners participating in the race, which draws tens of thousands of professional and amateur athletes, and that he doesn't know where they all were when the explosions happened.

"I hope everyone's OK," he said.

Tapia placed ninth in the marathon, according to the race's website.

Boston Marathon officials posted about the incident on the event's Facebook page just before 1 p.m.

"There were two bombs that exploded near the finish line in today's Boston Marathon. We are working with law enforcement to understand what exactly has happened," the statement read.